Bird God Star (English: Makemake, pronounced:/ˌ m ː ki ː m ː ki ː/MAH kee MAH kee or/ˌ m ː ke ɪ m ː ke ɪ/MAH kay MAH kay)[1]，Official nameIs (136472) Makemake,[2]yessolar systemThe third largest known indwarf planet, alsoClassical Kuiper Belt ObjectsOne of the largest two.The diameter of ornithus is aboutPlutoThree fourths of.[3]
On March 30, 2024, the bird god will greet the sun.[9]
Bird God Star (English: Makemake, pronounced:/ˌ m ː ki ː m ː ki ː/MAH kee MAH kee or/ˌ m ː ke ɪ m ː ke ɪ/MAH kay MAH kay)[1]，Official nameIs (136472) Makemake,[2]Is the third largest known in the solar systemdwarf planet, alsoClassical Kuiper Belt ObjectsOne of the largest two.The diameter of ornithus is aboutPlutoThree fourths of.It is known that there is a small satellite of Avis, which is 1300 times darker than Avis, about 20900 kilometers away from Avis, and about 160 kilometers in diameter.The average temperature of Avis is extremely low (about 30 K (- 243.2 ℃)), which means that its surface is covered withmethaneAndethane, and there may also be solid statenitrogen。[4]
Originally known as 2005 FY9, the Bird God Star (later known as 136472) was created byMichael E. BrownIt was found by the leading team on March 31, 2005;On July 29, 2005, they published the discovery.On June 11, 2008,International Astronomical UnionInclude Bird God StarPlutonian Object In the candidate list.Pluto like objects areNeptuneThe exclusive classification of dwarf planets out of orbit was only Pluto andEris It belongs to this category.In July 2008, Avia was officially listed as a Pluto like object.
On April 26, 2016, scientists announced the discovery of the satellite of Avis:Io（MK2）。
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Bird God Star (Figure 2)
Discoverers: Michael E. Brown, Chad Trujillo, David Rabinowitz;
March 31, 2005Michael Brown The team led by the team discovered the bird god star, and on July 19, 2005Eris The discovery was announced at the same time, but two days later than the announcement of the pregnancy god star.
Although the relative brightness of Avis is relatively high (about one fifth as bright as Pluto), people have not found it for a long time. In fact, many darker objects in the Kuiper Belt have been found.This is because most asteroid hunting activities are close to each otherEcliptic(From the earth, the plane of the sun, moon and many planets) After all, the probability of finding an asteroid near the ecliptic is the highest.Therefore, in the early observation, people did not find the bird god star, which may be attributed to its high orbital inclination and its location when it was found: it was located in the northern skyBackseatAt the farthest place from the ecliptic.
Around 1930Clyde Tombaugh yesOuter Sea King StarIs searching, exceptPlutoIn addition, the bird god star is the only one whose brightness is enough for Tombaugh to observedwarf planet。During the period of Tombaugh's observation, Oryx was only a few degrees away from the ecliptic, close to Taurus andAurigaAt the junction of,Apparent magnitudeAbout 16.0, etc.Unfortunately, this location is also quite closethe galaxyIt's almost impossible for Tang Bo tofixed starFind the bird god star in the background.After discovering Pluto, Tombaugh has been searching tirelessly for many yearsplanetBut he never found the Bird God Star or any otherOuter Sea Uranus。
Temperature: 30 ～ 35 K [c] (assuming constant albedo);
Apparent magnitude: 16.7 (impulse);
Absolute magnitude: (H) -0.48.
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Outer Sea Uranus
The tentative name of Bird God Star when it was discovered and announced was 2005 FY9. Before the official name, the discovery team nicknamed it "Resurrection Rabbit" because it was discovered shortly after Easter.
In 2008, in order to comply with IAU's traditionalKuiper beltCelestial namingFor the rule of God of Creation, 2005 FY9 was officially named Bird God Star.This name is derived from the god who created human beings in the myth of the indigenous people of Rapanui on the Resurrection Island. Part of the reason for choosing this name is to retain the connection between the time of discovery and Easter.[6]
Physical characteristics
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Size and brightness
In March onBackseatWhen flushingApparent magnitudeAbout 16.7, etc., this photometric useAmateur astronomyHigh order telescopes can be observed.The surface temperature is estimated to be about 30K based on the high reflectivity of Oryx, which is close to 80%.The exact size of Avis is not very clear, but according toSpitzer Space Telescope According to the infrared observation and the estimation of the similarity between its spectrum and Pluto, its diameter is 1500+400-200 km.This value is slightly higher than 2003 EL61, making it the third largest exoplanet after Eris and Pluto.Because the absolute magnitude of Bird God Star is -0.48, its size also ensures that it can reachHydrostatic balance, has become the fourth dwarf planet in the solar system.
spectrum
In a letter to the journal Astronomy and Astrophysics, it was mentioned that in 2006, Licandro et alFrederick William Herschel The near-infrared spectrum observed by the telescope and Galileo telescope is very similar to that of Pluto.,It appears red in the visible spectrum, and the relative spectrum of Erin is relatively neutral (seeNeptuneColor comparison of celestial bodies).Infrared spectrumIt shows the presence of methane (CH ₄)PlutoandEris Yes, too.But its existence is more obvious than that of Pluto, so it is suggested that Avis may have a temporary atmosphere near the perihelion, just like Pluto
The spectral analysis of Avis also shows that there are large particles of methane crystals with a diameter of at least one centimeter on the surface, and a large number ofethane, probably because solar radiation is photolysis from methane.Unlike Pluto and Eris, the evidence shows that there is only a small amount of frozen nitrogen on the surface of Oryx, suggesting that the supply of nitrogen was stopped or consumed for unknown reasons in the early solar system.
atmosphere
Methane and the possible presence of nitrogen mean that there can be a temporary atmosphere on Oryx, a phenomenon similar to Pluto's near perihelion.If there is nitrogen in Avis, then nitrogen will become the main substance in the atmosphere of Avis.The existence of the atmosphere also provides a reasonable explanation for the loss of nitrogen: because the gravity of Avis is weaker than that of Pluto, Eris andTriton Bird god star may lose a lot of nitrogen due to atmospheric escape;Although methane is lighter than nitrogen, the vapor pressure of methane will be significantly lower than that of nitrogen when the surface of ornithos is at normal temperature (30-35 K), which will inhibit methane escape;The result of this process is that the relative content of methane keeps rising.
According to foreign media reports, through in-depth research, scientists found that a "dwarf planet" found near the edge of the solar system seven years ago was a frozen world without atmosphere and life.Scientists discovered the "bird god star" named after the Polynesian god in 2005, but until now, the size, shape and surface of this distant planet have been studied in detail for the first time.
It is two-thirds of Pluto, farther from the sun, and one of the five distant worlds that orbit the sun and are considered dwarf planets.But it is not as far from the sun as the largest dwarf planet known, Eris.A promising way to understand the phenomenon of star occultationEuropean Southern ObservatoryOur astronomers have a chance to find out whether there is an atmosphere in Avis.This problem has puzzled scientists for a long time. Now they find that this dwarf planet has no atmosphere[7]。
classification
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As of 2009, the distance between Avis and the sun was 52 astronomical units (7780000000 km);Almost the farthest from the sun in its orbit.The orbit of Oryx is very similar to that of Preemption: the orbital inclination is as high as 29 ° and the medium eccentricity is about 0.16.However, the orbit of ornithos is slightly farther from the sun at the semi major axis and perihelion.Its orbital period is about 310 years, longer than the 248 years of Pluto and 283 years of Pregnant God.Aphelion, and the planet Pregnancy God passed through the Aphelion in early 1992.
Bird god star belongs to the traditional ancient cypress belt celestial body in classification, which means that its orbit is far away fromNeptuneIt can keep stable for a long time.Is different from the one that will cross the orbit of NeptuneSmall Celestial Bodies of the Pluto, TraditionalKuiper beltThe celestial body has got rid of the orbit disturbance of Neptune;This is because there is a 2:3 orbital resonance between the small Pluto objects and Neptune, while traditional objects are farther from the sun than Neptune at perihelion.traditionKuiper Belt ObjectsThe relative eccentricity of is lower (e is lower than 0.2), soplanetThe same goes around the sun.However, the Bird God Star is still called an "alternative" in this group, because it is different from othersTraditional ancient cypress belt celestial bodyIt has a large rail inclination.There may be 11:6Track resonanceHowever, it needs further astronomical observation data to verify.
On August 24, 2006, the International Astronomical Union (IAU) released a new definition of planets, in which the celestial bodies orbiting the sun are clearly divided into three categories:“Small objects in the solar system”Its mass is too small to form a spherical surface by its own gravity;Although the dwarf planet has enough mass to form a sphere, it still cannot clear objects of similar size in its orbit;"Planets" not only have enough mass to form a sphere, but also can remove objects of similar size in their orbits.Under this classification, Pluto, Eris andCeresIs reclassified as a dwarf planet.
On June 11, 2008, based on the original planet classification, IAU further addedPluto like dwarf planetThis classification of dwarf planetesimals.Eris and Pluto belong to it, but Ceres is not.One unknown whether it has reachedHydrostatic balanceIf you want to be classified by IAU as a similar dwarf planet, you must have a high brightnessAbsolute magnitudeIt must be less than or equal to+1, which means that only Bird God Star and Pregnant God Star may meet this qualification.On July 11, 2008, the IAU/USGS Planetary Naming Working Group listed Ares as a Pluto like dwarf planet, making it officially recognized as a dwarf planet and the third Pluto like dwarf planet after Pluto and Eris.
track
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The distance between Avis and the sun is 52 astronomical units, almost at the position far from the sun in its orbit.The orbit of Oryx is very similar to that of 2003 EL61: high orbit inclination (29 °) and moderate eccentricity (e~0.15).However, the orbit of ornithus is slightly farther from the sun (on the semi major axis and perihelion), and its orbital period is about 310 years, longer than Pluto's 248 years.
satellite
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In April 2015, the Hubble Space Telescope observed the satellite of Avis, which is 20921km away from Avis.On April 26, 2016, American scientists announced the discovery of the satellite of Avis, named Avis One (MK2)
Ornithus is a member of the dwarf planet, located in the coldOuter solar system——The Kuiper Belt is full of countless wastes from the formation of the solar system - small frozen bodies.Since the discovery of Avis in 2005, astronomers have searched for the companion star of this frozen world many times.Now, with the help of the Hubble Space Telescope jointly operated by NASA and the European Space Agency (ESA), they have discovered one of its satellites[8]。
Environmental Science
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In April 2011, when the Andromeda passed in front of a background star, an international team of astronomers seized the opportunity to use the telescope on the mountain top to observe it.Astronomers found that when the bird god star passed in front of the star, it blocked its light, but the starlight disappeared and reappeared in a very sudden way, rather than gradually fading and increasing, indicating that the dwarf planet was not significantatmosphere。
People have always thought that the Bird God Star has good conditions for forming the atmosphere, which shows that we really know too little about this mysterious celestial body.
Bird god star was found in 2005, it is a colddwarf planet, the diameter is aboutPluto2/3 of, 51 from the sunAstronomical unit。Previously, it was thought that ornithus might have a thin seasonal atmosphere similar to that of Pluto.
Because of its small size and long distance, the ornithos has brought difficulties and challenges to astronomers.Although the occultation event of Avis in April 2011 lasted only one minute, astronomers seized the opportunity to measure the volume, mass, density andreflectivityAnd so on.It is observed that the reflectivity of the Bird God Star is about 0.77, and the density is estimated to be 1.7 ± 0.3 g/cm ³, indicating that it is a small body composed of rocks and ice.[5]
Japanese history
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On March 30, 2024, the bird god will greet the sun.Wang Kechao, director of science popularization at the Zijinshan Observatory of the Chinese Academy of Sciences, said that solar eclipse is a good time to observe extraterrestrial objects.In the future, amateur astronomers can try to take pictures of Avis with professional telescopes and cameras for a long time.[10]
